Note that there are only two 'name' values the charm knows about: 'requirements'
and 'nova'. These repositories must correspond to these 'name' values.
Additionally, the requirements repository must be specified first and the
nova repository must be specified last. All other repostories are installed
in the order in which they are specified.

The following is a full list of current tip repos (may not be up-to-date):

Configuration

(string)
Only used when migration-auth-type is set to ssh.
.
Full path to authorized_keys file, can be useful for systems with
non-default AuthorizedKeysFile location. It will be formatted using the
following variables:
.
homedir - user's home directory
username - username
.

(int)
This value dictates the number of replicas ceph must make of any
object it stores withing the nova rbd pool. Of course, this only
applies if using Ceph as a backend store. Note that once the nova
rbd pool has been created, changing this value will not have any
effect (although it can be changed in ceph by manually configuring
your ceph cluster).

(string)
Tell Nova which libvirt image backend to use. Supported backends are rbd,
lvm and qcow2. If no backend is specified, the Nova default (qcow2) is
used. Note that rbd imagebackend is only supported with >= Juno.

(boolean)
If True nova-compute will install neutron packages for the plugin
stipulated by nova-cloud-controller. The option is only available for
backward compatibility for deployments which do not use the neutron-api
charm. Please do not enable this on new deployments.

(string)
Used by the nrpe-external-master subordinate charm. A string that will be
prepended to instance name to set the host name in nagios. So for
instance the hostname would be something like:
.
juju-myservice-0
.
If you're running multiple environments with the same services in them
this allows you to differentiate between them.

(string)
Repository from which to install. May be one of the following:
distro (default), ppa:somecustom/ppa, a deb url sources entry or a
supported Ubuntu Cloud Archive (UCA) release pocket.
.
Supported UCA sources include:
.
cloud:<series>-<openstack-release>
cloud:<series>-<openstack-release>/updates
cloud:<series>-<openstack-release>/staging
cloud:<series>-<openstack-release>/proposed
.
For series=Precise we support UCA for openstack-release=
* icehouse
.
For series=Trusty we support UCA for openstack-release=
* juno
* kilo
* ...
.
NOTE: updating this setting to a source that is known to provide
a later version of OpenStack will trigger a software upgrade.
.
NOTE: when openstack-origin-git is specified, openstack specific
packages will be installed from source rather than from the
openstack-origin repository.

(string)
Specifies a YAML-formatted dictionary listing the git repositories and
branches from which to install OpenStack and its dependencies.
.
Note that the installed config files will be determined based on
the OpenStack release of the openstack-origin option.
.
For more details see README.md.

(boolean)
If True enables IPv6 support. The charm will expect network interfaces
to be configured with an IPv6 address. If set to False (default) IPv4
is expected.
NOTE: these charms do not currently support IPv6 privacy extension. In
order for this charm to function correctly, the privacy extension must be
disabled and a non-temporary address must be configured/available on
your network interface.